Cutter clearance gauge



Oct. 16, 11928.'

F. L. GILLETT CUTTER CLEARANCE GAUGE Filed sept. 8, 1927 F F i 69 i 2 ll I 50 40 36 'l 27 f A l "fr 20 2 l G "Uhy I 57 /a l 22 5 45 25 /H /3' AC\\ H T TOR/XE Y.

lpatented Oct. 16, 192g.

UNITEDsT-Ares iafrfENT()1.4.1.1'013,i e

,'FRANKIL. GiLLnTT, oF Los Antennas, CALIFORNIA. V

Appucatiqn mea september s, 19272 seriarNo. 213,131.

My invention relates to gauges and more particularly to acutter-'clearance gauge.

Milling cutters and similar cutters are often used in shop practice. Itis ott-en desirable to determine the clearance angle of the teeth ofthese cutters when the cutters are being sharpened, or to check theclearance angle on a cutter already sharpened.

VIt is an object of my invention togprovide a gauge for measuring anangle of a cutter tooth. c

Inr sharpening such a cutter, it is mounted on an arbor in a milling orgrinding machine. Cutter clearance gauges now on the market require thatthe cutterbe removed from the arbor before an accurate check on theclearance angle can be obtained. This is due to the fact. that thegauges novvon vthe market have a bossV or otherA means adaptedtocentralizein the opening through the center ofthe cutter.`

L It isy an object of'my invention to provide a cutter clearance gaugewhich will measure the clearance angle andcother angles of 'a cutterWithout removing `the cutter from 'its arbor or supporting shaft.. i

A further object of my invention isto provide ,a cutterclearancegaugewhich is adapted to operate ona Wide numfber'of sizes 'and types ofcutters.

Another object of my invention is to provide a cutter clearance gaugeWhich reads the cutter clearance angle directly on a scale. VStillanother object ofmy invention is lto provide such a gauge which may bekoperated by theuse' of onehand only. e Another object of my inventionis to -'pro vide a cutter clearance gauge which Willlnot cast heavyshadows on the tooth, tlieangle oit' y the" line `(fj-C "thisvsurfafce18 is c`o1n Vmonly termedy the 'secondary'fangle of the Which is to'bemeasuredfj Another objecty of my yinvention is to provide a cutterclearance gauge Whichmeasures `an angle of a tooth with reference to apreceding and a succeeding tooth. Still a further object ofmy inventionis'to provide a cutter clearance gauge :Whichsimultaneously contacts thecutting edges of'a preceding and a succeedingtootl'rinmeasuring theangles of an intermediate tooth.l

Still another object of inyinventionisto lprovide a cutter clearancegauge which may Aalso be used to check the clearance angle' onside-cutting cutters. l `Another object otmy 'invention is to provide a"gauge which will measure secondary angles of a tooth of a cutter.; v

Further objects and advantages of my 'inventionvvill be made evident inthe following description.` Inthe drawings, y y

Fig. 1 'llustrates a front view of the cutter clearance gauge. of myinventionfwhen used formeasuring the clearance angle of a cuttertooth.rv l

Fig. 2 is an end view of'my device talfen aS indicated by the arrow 2 ofFig.` 1L 1 *Fig 3 is a vertical cross section ofthe slider ofv myinvention Yand is taken lsubstantially along `the line 3 3 of Fig. 1.(

Fig. t is a `front view ofthe slider7 partially hrokenfaway. l i"Thegauge of ymy invention is adaptedto measure various angles `on'acuttersuch asis commonly usedin machine-shop practice.

Such a cutter 10 is shown `in-Ig. 1, this cutter having teeth "11 spacedaround the periphery thereof. l Each tooth 11 has acuttingledge 13formed at the junction ofa surface Hand a beveled surface 15j A line A-Ain Fig. 1

joins the cutting edgefofatooth l1 and the axis 'about which the cutter10 isfrotated When in operation A line (lf-C is drawn through the"cutting edge 413 perpendicular toy the line A-A. `Another line B4B isdrawn throughthe cutting edge and liesinl the beveled `surface 15.- .Aniangl'eD is subtended vbetween the lines B-B `and C`-C. This angle D iswhat:` is commonly termed the-cutter clearance anglelof t-he tooth.' "Itis necessary in su'ccessfluljoperation that this yangled) be an anglegreater than zero degrees.

In certain cutters a`-surface 18 forms the back of each tooth 11. Theangle` between tooth. l/Vith `these denitionsinl mindy the 'usefulnessof my device sheuld be apk-parent..

f My device is primarily de'sigmidv to meas- :ure `the cutter clearanceangle D; As shown tween thetooth-contacting surface 22 and the tooth '24may conveniently -be'along the cutting edge* 1,3"of the tooth 241asindi-Y. are adapted Vto engage the lower edge of the cated in Figl. The bladehas a leg 27' extending ,leftward t'herefrorn.l Adapt ed to`alongj-theflegl27 'is' a slider 30v of leg 27. The engager v is heldagainst'the .loweredge ofthe legl27-by means of av'c'ontactor 38 whichrides along the upperedge of the leg 27. This contacter isforced intoengagement with the leg 2,7'by`means of a thu-,inbvlscrew V40 whichisthreaded kthrough the bridge V33 1 and bea-rs against ther .upper -edgeof the contactor 38. -By tighteningthe -bearsagainst the arm l .passesthrough `the elongated groove' 51 of about thel aXisof the pivot pin 52.

thumb screw 40 the slider 30 is prevented from movingrelative tothe leg27.` U

The engager; 35has notches 43 and 44 inthe lowerends,thereof,y oneonfeach edge of the slider 30. v The 'Ibott'ommof .eitheroffthesenotches is adaptedr to'engage the ycutting edge ofa tooth precedingjinsequence' the tooth 25 which is to be measured. The notch43-is designedfori use with` Widely separated teeth `and the notch 44 is-,desig'ned,for use with Ateeth close to each 'oi'.lier. l Either -not ch maybeused by1reversingthe` slider 3() on the leg 27. -A Alinefthrough .thelower tooth contactin'g surface 22 will pass through' the"bottom ofeachofthe n0tches'f43fand 44. Y .y l j vAn yarm .50, having an elongatedkVslot'51 along the aXisthereof, isslidably and rotatably connected tothe :blade 20jbyapivot pin 52. Thispivot pin vhas a spring arbor k54mounted thereon, this springarbor bearing -agai-nsta "washer 55. Thewasher 55 also 5l). VThe pivot-,pin5`2 the arm and the blade20, andhasfa nut 57 screwed I thereon. By suitably tightening the nut 57it'ispossible to swing the arm 50 At the sametimeit is possible to slide theQ arm`50 relative to the blade 20, the pivot'. pin 52 following theelongated groove 51.l The lower endvof the arm 50 provi les a surface 60whichI is adapted to come in contact with the beveled surface of thetooth to be measured.v The surfaceGO is preferably at right angles tothe axisofthe-swingingarmf50.A Y

f The upperend of the blade 2() l provides a protractor scale havingmarkings atthe upper 'end thereof. A line 68 is .scribed along the axisof the arm 50, and is vadapted toform al reference line forreading theprotractor markings It Ais j a comparatively easy task to operaternyinvention. JT slider so set that ay ,portion of the tooth-contactingly surface 22 willcontact the tooth 24 at 7'the cutting edge Y thereofwhen one ofthe' notches'contacts the cutting edge of the ktooth 45. Thissetting is not critical as 'may be seen from the drawing inasmuch a'sthecontacting surface 22 is of a considerable length. The gauge is thenheld -invone hand and one finger placed pivot is rotated about the pivotpin 52 until the surface GOlies along the line C-C, the line 68 on the`arm 50 will fall at the Zero point on the protractor scale. If now ythearm 50 is lpivotedf:about the pin 52 and lowered slightly, it ispossible to bring the surface'() into contactwith the beveledsurface 15of the tooth 25. vThis/position `is indicated in'lig. I 1, and"ig-...the `normal position for reading the clearance angle of a. tooth.It will be noticed fromFiglthat the line 68 ofthe arm 50 corresponds toa.y readingof five degrees on the `protractor scale. vThis angle'wouldybe*y the clearanceangle on the tooth 25.

It is notfne'cessary that t-hetooth-contact- .ing surface' to'uchayytooth which is immediately adjacent to the tooth being measured nor `isit necessary that one of the notches43 or 44 contact a= tooth whichlis.-iminediately adjacent to the tooth beingmeasured. The

vgauge would"work equallyfwell ifthe contacting surface 22 were placedvincont-act su y with the cutting edge `of a tootlrTO, and the notchwere'plac-ed in contactlwith the cutting edge of a tooth 71. -Thus,itshould be `runder-` stood that the terms"succeeding tooth and precedingtooth, as used inthe appended clairns,lshould not be' limited. to .teethimme diately adjacent the tooth beingV measured. It is only necessarythat there be an odd number of teethbetween the tooth contacted by thesurface 22 rand that contacted by the notch,vthe tooth being measuredbeing the central of thisoddnumberof teeth. llnother words,'theremustbean equal number of teeth between 4the.toothbeing measured andl theteeth'in contact ywith lthe/surface 22 and the lnotclr respectively.fThus my inventioncan be used on extremely small cutters having a veryclose spacing of teeth. Iny such an event the surface 22 and the notchmight contact teeth which were almostvdiametrically opposite,`and thecorrect clearance anglek of ,the teeth could be correctly obtained'. Inthis case, however, it mightbe necessary to remove the slider 30- fromthe leg 27and ro tateit through an angle of 180 degrees about itsvertical `aXis and reinsert fit thereon. This wouldbring the notch 43into contact witha tooth, .which would be necessary in thel event thattheV bottom ofthe lnotch 44 did not contactthe cutting edge of t-hetooth13.

. My gauge is also applicable to-measuring 'the' secondaryy angle of atooth. Inme'asurmovedthat the surface 60 thereof Would be i` of a cuttertooth, the combination of: a frame adaptedto simultaneously contact apreced1 Y teeth formedon one side of a cutter.

in'contact With the surface 18 of the tooth 25. At this time the correctsecondary angle could be read on the protractor scale, ,this angle beingthe angle betweencthe lineC*C and the surface 18. f A y f f My gaugecould also be used in measuring the clearance angles and secondaryangles ofk Such side-cutting teeth are comparatively common inniachine-shop practice', and itis often dif-V ficult to determine theclearance angle by present methods. rheoperation ofthe device would besubstantially the same in this case as in the v'case of a cutter havingteeth spacedl around the periphery thereof.

I claim as my invention:

l. In a gauge adapted to measure an angle of a cutter tooth, thecombination of: a frame adapted to simultaneously contact the cuttingedges of a preceding and a succeeding tooth; and means pivoted to saidframe for measuri ng an angle of said cutter tooth.

Q. In a gauge adapted to measurean angle ing and a succeeding tooth; andmeans pivoted to said frame for measuring an angle of said cutter tooth,

8. In a gauge adapted to measure an angle of a cutter tooth; thecombination of: a frame adapted to contact the cutting edges of apreceding' and a succeeding tooth; an arm adapted to contact a beveledsurface of said tooth; and means for indicating the angle of saidbeveled surface.

Il. In a gauge adapted to measure an angle of a cutter tooth, thecombination of: a frame adapted to vcontact a preceding and a succeedingtooth; an arm adapted to contact a beveled surface of said tooth; andmeans for indicating the angle of said beveled surface. l l' A 5. In agauge adapted to measure an angle of acntter tooth, the combination of:aframe adapted to simultaneously contact. the cutting edges of apreceding and a succeeding tooth; an arm pivoted to said frameA andadapted to contact a `beveled surface of said vtooth g 'and a scalecarried by said frame, saidV scale ard said arm "indicating the angle`of said beveled surface.

6. In a gaugeadapted to measure anangle of a cutter tooth; thecombination of: a frame adapted to simultaneously contact a precedingand asucceeding tooth; an arm pivoted to said frameand adapted toContact a beveled Y surface of said tooth; and a scale carried bysaidframe; said scale and said arm indicating the angle of said beveledsurface.'

7. In a gauge adapted to measure an angle of a cutter tooth; thecombination of an ad? Vinstable frame adapted to simultaneously Contactthe cuttting edges of a preceding and a succeeding tooth; and meanspivotedto said frame for measuring an angle of.` said cutter tooth. i t1 f y8. In agauge adaptedto measure an `angle of a cutter tooth7 thecombination of: an adjustable frame adapted to simultaneously contact `apreceding and a succeeding tooth;

and means'pivoted to said frame for measur ying an angle ofsaidcuttertooth.

9, In afeau'ffe ada )ted to measurefan anale L1 D 2D of cutter toothythecombination of: a frame adapted to simultaneously contact the eut-"tiugedges of `a preceding anda succeeding adapted to contacta beveledsurface of saidV tooth; and a'scale disposed on said frame; said scaleand said arm indicating the angle of said beveled surface.

1l." In a gauge adapted to measure the am gle of a cutter tooth, thecombination of: a blade adapted to contact a succeeding tooth; a slidercarried by Said blade; said slider being adapted to contact a precedingtooth; a scale disposed on said blade; and an arm carried by said blade,said arm bein adapted to ycontact a beveled surface of said tooth and toindicate the angle of said beveled surface on said scale.V n i c 12. Ina gauge adapted to measure the aligle of a cutter tooth, the combinationof: a blade adapted to Contact the cutting edge of a succeeding tooth; aslider carrier by said blade, said slider being adapted to Contact thecutting edge of a preceding tooth; a scale disposed on said blade; andan arm carried by said blade, said arm being adapted to contact abeveled surface of said tooth and to in= dicate the angle ofsa-idbeveled surface on said scale. c f

`V13. In a gauge adapted to measure the angle of a cutter tooth, thecombination of: a blade adapted to contact a succeeding tooth; a slidercarried by said blade,asaid slider being adapted to contact a precedingtooth; a scale secured to said blade; and an arm slidably and rotatablycarried by said blade7 said arm being adaptedl to contact a beveledsurface of said tooth and to indicate the angle of said edge on theother end of said frame and in' line with the Vertex ofV said notch,said `straight .edge eontactingthe Cutting edge ofa tooth lsucceeding insequence the tooth being measured; and means carried by said frame Jformeasuring an angle of the said ltooth being measured.

15. Ina gauge adapted to measure an angle of a cutter ltooth, thecombination of: a frame yadapted to simultaneously Contact Jcheeuttingedges of a preceding and a succeeding tooth; an arm Carried yhysaid frame and adapted to Contact a beveled surface of said tooth; andal scale Carried by said frame, said Cale and said arm indicating rtheangle of said beveled' surface.

16. 'A-.eoinhination-as defined in claim 14 in and including a scale fordirectly reading -the angle to be measured.

1.7. A eon'ihination as defined in claiml 14 in which said-notch may bemoved with its vertex in line with, said straightedge.

In `Jcestimony whereof, I have hereunto Set my hand at LosAngeles,California, this lst day of August, 1927. f

i FRANK L. GILLETT.

